(19) |
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(11) |
EP 0 159 579 A3 |
(12) |
EUROPEAN PATENT APPLICATION |
(88) |
Date of publication A3: |
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16.03.1988 Bulletin 1988/11 |
(43) |
Date of publication A2: |
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30.10.1985 Bulletin 1985/44 |
(22) |
Date of filing: 01.04.1985 |
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(84) |
Designated Contracting States: |
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DE FR GB IT |
(30) |
Priority: |
26.04.1984 US 604112
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(71) |
Applicant: ALLIED CORPORATION |
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() |
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(72) |
Inventors: |
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- Hopkins, Ronald James
()
- Thomas, Evan Gower
()
- Kieta, Harold J.
()
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(54) |
Soluble surfactant additives for ammonium fluoride/hydrofluoric acid oxide etchant
solutions |
(57) Silicon trioxide etching solutions with soluble surfact additives are provided. The
improved silicon dioxide etchants are produced by adding soluble perfluorinated surfactant
additives to standard oxide etchants in the manufacture of integrated circuits. These
surfactant additives are unique because they remain dissolved in the oxide etchant
(ammonium fluoride/hydrofluoric acid mixture) even after 0.2 micron filtration. In
addition, the filtered solutions retain their surface active properties and are low
in metallic ion impurities. The surfactant additives provide etchant solutions with
lower surface tensions, which improves substrate wetting and yields better etchant
performance. The surfactant does not leave residues or adversely affect etchant profiles.